Mpiallreduce probelm

Hello there, a quick question about MPIALLREDUCE; I used this function in the following script

mpiComm Comm(mpiCommWorld, 0, 0);

real nubl = mpirank;
real nubg=0;

mpiAllReduce(nubg, nubl, mpiCommWorld, mpiSUM);

cout << “finnal SUM " << nubg << " elements” << " mpi "<< mpirank << " has " << nubl << endl;

real[int] S1(4),S2(4),S(4);
real MP;
MP = mpirank*2;
S = [0,0,0,0];
S2 = [MP,MP,MP,MP];

mpiAllReduce(S,S2, mpiCommWorld, mpiSUM);

cout << S << endl;

the data types are real and real[int]; it seems mpiALLReduce reinitialized my data; But I believe this function works fine when I am doing domain decomposition method;

You are switching all parameters, it is mpiAllReduce(in, out...), not mpiAllReduce(out, in...).

damn it, Thx for pointing it out; :joy: